Echo

Echo

Introduction : The sound wave travelling in the form of wave has the similar property of reflecting from a surface from where it is incident. The sound after reflection travels back towards the source and if it reflect again , the process goes on until the energy of the wave becomes zero. The reflection of the sound after reflection from rigid surface is called as Echo.

Condition for echo :  To hear a distinct echo , the  reflecting surface should be at a minimum distance of 17m (approx) from the source. the human brain have the tendency to retian any sound for about 0.1 second. If another sound reaches the human ear before 0.1 seconds , the sound is heard for prolong time and this phenomenon is called as reverberation.

At 22⁰C , the velocity of sound in air is 340m/s. The sound retains in the brain for about 0.1 second. Thus the distance for echo will be as,

Distance = Speed x time

Distance = 340 x 0.1

Distance = 34.4 m.

Thus the distance between source and sound would be half  i.e 17.2 m. 

_{│<<<Factors affecting velocity│   │Quality of sound>>>│}